The present invention relates generally to compositions and methods for disinfecting the surface of animal carcasses and in particular to a composition and method including certain fatty acids to kill enteric pathogens and spoilage organisms located on the surface of animal carcasses.
Bacterial contamination of animal carcasses continues to be a major problem in the meat processing industry. Enteric pathogens and spoilage organisms such as Salmonella, Campylobacter, Listeria, Pseudomonas and Enterobacteracae seem to be omnipresent particularly Salmonella and Campylobacter in the poultry environment. These bacteria appear to adapt to changes in the environment and have survived numerous improvements in sanitation, antibacterial drugs and other chemical treatments.
Authorities differ in opinion as to how and when carcasses become contaminated with the Salmonella bacteria. Some authorities argue that the Salmonella bacteria is on the skin of most of the chickens entering processing facilities. They further argue that little cross contamination of the carcasses occurs during processing due to existing sanitizing practices. However, existing sanitizing practices do not effectively reduce or eliminate the Salmonella bacteria already on the chickens, especially bacteria that are in pores or other protected areas on the skin. These protected bacteria are spread about the chicken carcasses during processing, so most of the carcasses leaving the processing facility are still contaminated with these pathogens.
Others argue that the Salmonella bacteria is attached to relatively few of the chickens entering processing facilities and most of the carcasses are cross contaminated with the Salmonella bacteria during processing. For example, Salmonella may be transferred from the excrement of one carcass to the feathers of another while in a poultry transport container.
In order to reveal the numerous possibilities for Salmonella contamination in the processing of poultry, the various steps of the process are briefly set forth. Usually, the process begins with the slaughtering of a chicken and then immersion of the carcass into a scald tank. The scald tank temperature is from about 50 to 60 degrees Centigrade. The carcass is then plucked and eviscerated.
The carcass is then placed into a chiller tank. The United States Department of Agriculture (USDA) Safety and Quality Service regulations require that the chicken carcasses be cooled to below 40 degrees Fahrenheit within four hours after slaughter, that two quarts of water must flow from a chiller tank for each chicken carcass cooled. The carcasses must not gain more than eight percent water weight during the entire procedure. Other requirements exist for different types of poultry such as turkeys, and are typically dependent upon the size of the animal. Chillers used in the cooling process normally use cold water or a water and ice slush to remove animal heat from carcasses. Cooling water in the chill tank is maintained at approximately 34 degrees Fahrenheit (F). The carcasses are typically tumbled through the chiller and in the process blood, lipid, dirt, bacteria and other particulate matter wash off the carcass and become suspended in the chiller water.
It has been suggested that various organic acids, such as acetic and lactic be added to the scald tank in an attempt to disinfect the carcasses. Chlorine has been added to both the scald tank and the chiller tank for this purpose. Although these tactics may be successful in reducing or eliminating cross contamination, none of these treatments have been completely successful in eradicating Salmonella on the chicken. Many of the acid treatments are successful in high concentration to kill Salmonella but such high concentrations adversely affect the organoleptic appearance of the carcass or render the skin easily bruised and damaged during the remainder of the processing procedure.
It has previously been shown in certain industrial and commercial applications that certain fatty acids have an inhibitory or bacteriocidal effect on certain bacterial species. In particular, mixtures of fatty acids have been utilized for sanitizing processing facilities, such as pipelines; however, the literature does not disclose direct use on animals or animal carcasses. Furthermore, not all fatty acids or compositions containing various mixtures thereof would be acceptable for use on animal carcasses. Certain short chain fatty acids having from about 4 to 7 carbon atoms have a particularly rancid, obnoxious odor, making them unacceptable if used in high concentrations. The low water solubility and surface tension of fatty acids also poses a difficulty in preparing sanitizing solutions having fatty acids dissolved therein.